WASHINGTON (CN) – Environmental experts called the use of chemical dispersants on the BP oil spill an “experiment” with “massive unknowns” in a Senate hearing Wednesday, as federal officials both defended BP’s use of the chemicals and called for more research.
“The long-term effects on aquatic life are still significantly unknown,” said Environmental Protection Agency Assistant Administrator Paul Anastas during a joint hearing of the Senate Environment Committee and an oversight subcommittee.
Since the April 20 Deepwater Horizon explosion, cleanup crews have emptied 1.8 million gallons of dispersants into the Gulf of Mexico. The dispersants work to break down the spilled oil into smaller droplets that are rapidly degraded by microbes, resulting in an organic compound of carbon dioxide and water.
After testing thousands of water samples, the EPA found that dispersants do not linger in the ocean environment. The EPA said the presence of dispersants “declines rapidly” the greater the distance from the wellhead, and said it has not detected any dispersants along Gulf coastlines or in coastal wetlands.
The agency also found that, while dispersants tested alone are slightly toxic and oil tested alone is moderately toxic, an oil-dispersant mixture tests as no more toxic than the oil itself.
But federal officials and experts pointed out numerous problems with the sampling and monitoring process.
“We didn’t even have a good technique to collect samples at depth,” said Louisiana State University Professor Dr. Edward Overton. He said sampling containers got covered with oil while traveling to the wellhead, making it impossible to tell if the samples were accurate.
Witnesses also explained that oil changes as it leaves the wellhead and goes through different stages of weathering, impacting its toxicity.
“It’s an elusive target,” Overton said.
University of Rhode Island Oceanography Professor Dr. David Smith added that there’s no data on dispersants applied in such unique deepwater spill conditions. The oil spewing out of the wellhead was coming out at a temperature of 100 degrees Fahrenheit and hitting cold water, Smith explained, a previously unstudied circumstance.
Smith said the industry’s entire knowledge of dispersants before the BP spill came from applying them on the surface, and because there is less oxygen and a slower rate of degradation at deeper water depths, the oil plume will be more persistent below the surface.
Texas Tech University Professor Ronald Kendall called the use of dispersants in the Gulf a “massive ecological toxic experiment” in need of in-depth, peer-reviewed research.
“We have no idea what the deepwater injection of dispersants into the water column … impact is,” Kendall said. “Dispersants are a tool, but they need to be fully researched … to truly apply them in the best stewardship possible.”
Smith said the impacts “may be less noticeable, but they could be more devastating than oil washing ashore.”
Kendall compared dispersants to pesticides, but said that while pesticide manufacturers had to provide both acute and chronic data about the substances in order to be registered, dispersant manufacturers were only required to provide acute data. As a result, Kendall said, it was impossible to evaluate the substances’ toxic impact on the environment.
“Their use is clearly a lose-lose situation,” said Oceana senior scientist Jackie Savitz. “The decision to use dispersants may have saved some birds in marshes while increasing the impacts on fish and other marine life. How can we say what is more important?” She called on the government to stop offshore drilling altogether, saying, “It’s a tradeoff.”
When asked whether the decision to use dispersants was the right call at the time, Anastas of the EPA said the decision was “not taken lightly.”
“That said, when you look at all the tools to combat this strategy — the skimming, containment — dispersants have shown to be one important tool in that toolbox,” he said.
“I’m not suggesting that we have perfect knowledge,” Anastas added. “I’m not suggesting that we don’t need more research. I’m actually saying straight out that it is important that we keep asking these hard questions.”